Gas turbine engines include a combustor where fuel and air are burned in order to produce a high energy gas stream. The apparatus and method by which fuel is delivered into the combustion chamber plays an important role in determining combustor performance. Successful combustion depends upon consistance fine droplet atomization of the fuel.
Two primary methods of atomizing fuel are in current use. The first involves a pressure atomizer in which fuel is forced under pressure through a small orifice from which it emerges as a multitude of high velocity atomized fuel droplets. A second method is by use of an air blast atomizer in which liquid fuel is shattered into droplets by the force of high velocity air.
Both pressure atomizers and air blast atomizers include a fuel injector as well as means for introducing and mixing air with the fuel. Typical of the latter is a swirl cup or swirler which is designed to admit air into the combustor as well as ensure thorough mixing with the injected fuel.
Normally, the swirler is rigidly attached to the combustor with the fuel injector being removably connected to the swirler. This is necessary so that the fuel tube may be removed from the combustor for periodic inspection. Furthermore, temperature swings in the combustor result in thermally induced motion of the combustor and swirl cup. Such motion necessitates a sliding fitting between the fuel injector and the swirler. Such fittings may be objects to large forces which may result in undue wear. As a consequence, these fittings are costly to fabricate and repair and represent a significant portion of the combustion system weight.